DESCRIPTION: Electron cryo-microscopy (cryo-EM), particularly single particle cryo-EM, has recently experienced tremendous successes in terms of achievable resolution. It is now possible to determine near atomic structures (< 4 ) of a wide range of biological complexes without crystals, from samples ranging from large viruses with icosahedral symmetry, to ribosomes without symmetry and down to small integral membrane proteins such as ion channels. The goal of this proposal is to establish a high performance Linux computer cluster of 640 CPU cores that is optimized and dedicated to process images for near atomic resolution single particle cryo-EM. Establishing such a computer cluster is a critical step towards routinely determining cryoEM structures at near atomic resolution for a broad array of macromolecular complexes. Many biomedical research projects funded by NIH, particularly those requiring structural determination of previously un-crystallizable complexes, will benefit from such technological advancement. All developed software will be freely provided for research community.